Revert "io/router: try all handlers if a key don't match the focus ancestor tree"

This reverts commit 28c206fc78. The commit
introduced counter-intuitive behaviour as demonstrated by #503. In the
meantime, topmost handlers now receive all unhandled key.Events[0], which
should cover the use-cases that motivated the original commit.

[0] https://gioui.org/commit/0dba85f52e5131c03d903c84355fb90cdb978811

Fixes: https://todo.sr.ht/~eliasnaur/gio/503
Signed-off-by: Elias Naur <mail@eliasnaur.com>

io/router/key_test.go

@@ -363,11 +363,11 @@ func TestKeyRouting(t *testing.T) {
 	r2.Queue(A, B)
 
 	// With focus, the events should traverse the branch of the hit tree
-	// containing the focused element, and then every handler.
+	// containing the focused element.
 	assertKeyEvent(t, r2.Events(&handlers[4]), false)
 	assertKeyEvent(t, r2.Events(&handlers[3]), true)
 	assertKeyEvent(t, r2.Events(&handlers[2]), false)
-	assertKeyEvent(t, r2.Events(&handlers[1]), false, B)
+	assertKeyEvent(t, r2.Events(&handlers[1]), false)
 	assertKeyEvent(t, r2.Events(&handlers[0]), false, A)
 }
 

io/router/router.go

@@ -221,12 +221,6 @@ func (q *Router) queueKeyEvent(e key.Event) {
 		n := &pq.hitTree[idx]
 		if focused {
 			idx = n.next
-			if idx == -1 {
-				// No handler found in focus ancestor tree.
-				// Try all handlers.
-				idx = len(pq.hitTree) - 1
-				focused = false
-			}
 		} else {
 			idx--
 		}